The present invention relates to a photographic printer for printing an image of a picture frame of a film onto photographic paper.
Films from which prints are made tend to become scratched when transported in various photographic apparatus such as a camera, a developer, a negative film inspector, etc. These scratches usually extend in a lengthwise direction of the film and appear on prints as defects.
There are two well known types of photographic printers: diffusion type printers and condenser type printers. A typical diffusion type photographic printer which is widely utilized is shown in FIG. 5, and has a square shaped mirror box or tube 12, used as a diffuser, and disposed between a negative film 10 and a lamp 11. The mirror box 12 consists of an open ended mirror tube 20 with mirrored inner walls and diffusion plates 21 and 22 attached to the top and bottom of the mirror tube 20. Each diffusion plate 21, 22 is made of a matte glass plate or a milk white plastic plate. The negative film 10 is placed below and close to a framing mask 16 and is illuminated by the lamp 11. When a shutter 15 is opened, the light emanating from the lamp 11 enters the mirror box 12 and is diffused thereby. After passing through the negative film 10, the diffused light is focused on a photographic paper 14 placed over a framing mask 17 at an exposure station by means of a printing lens 13 to create a latent image of the negative film 10.
Diffusing the light from the lamp 11 prevents non-uniform distribution of light over the negative film 10 and contributes to providing high quality prints that are free from scratches on the negative film.
The diffused light passing through the mirror box 12 shows a substantially isotropic distribution, as shown in FIG. 5, but uses the light emanating from the lamp 11 inefficiently. To illuminate the negative film 10 with a sufficient amount of light, it was thought that the lamp 11 should be very bright. However, this causes a great amount of heat and increases the running cost of the photographic printer.
The condenser type photographic printer uses the light quite efficiently, but is disadvantageous in that scratches of the negative film will appear as defective images on prints.